Images

blog posts

CHAMPAIGN, lll. - Whenever it hears an unfamiliar song from a male of the same species, the zebra finch stops chirping, hopping and grooming. It listens attentively for minutes at a time, occasionally cocking its head but otherwise immobile. Once it becomes familiar with the song, it goes back to its busy routine. (See video.)

University of Illinois cell and developmental biology professor David Clayton and his colleagues found that microRNAs in the zebra finch brain respond when the bird hears a new song.

In a new study, researchers discovered that levels of microRNAs - short lengths of ribonucleic acid that appear to regulate protein production - go up or down in the songbird brain after it hears a new song. These microRNAs likely represent a new class of regulatory agents that fine-tune the brain's response to social information, said University of Illinois cell and developmental biology professor David Clayton, who led the study.

MicroRNAs are part of a new frontier in genomic biology: the 90 percent of human DNA that doesn't code for proteins. This "dark matter of the genome" includes genes that are transcribed into many different types of RNA molecules. Scientists are still working to decipher their various structures and functions.

Previous studies found that brain microRNAs "undergo dramatic changes in expression during development and aging and have been functionally implicated in neurological disease," the authors wrote in their paper in BMC Genomics. MicroRNAs appear to regulate the expression of protein-coding genes by binding to messenger RNA (mRNA) transcripts, the blueprints for proteins, before they can be translated into proteins.

Clayton and other researchers have documented changes in the expression of many mRNAs in the songbird brain after it hears an unfamiliar song. But no studies have, until now, found evidence that microRNAs also contribute to the process by which the brain responds to its environment.

"The question that we started with was, are there microRNAs that are showing a response to song in the brain?" Clayton said. "And the answer is clearly yes, there are. The bigger question that we don't have an answer to yet is what are they doing?"

The study team, which included researchers from the Baylor College of Medicine and the University of Houston, also identified a microRNA that went up in males and down in females after the birds heard a new song. The gene for this microRNA is on the Z

Watch as a zebra finch hears familiar and unfamiliar songs. | Video by David Clayton